NASA Perseverance Rover
7 minutes of Terror
This is an appreciation post for the amazing feat of science and engineering that took place on February 18, 2021. In case you missed it, NASA landed a rover safely on Mars named Perseverance. While it’s easy to look at this as another robot crawler on the surface of a nearby planet, I think that analysis is way off. For one, Mars isn’t that close (the rover had to travel 293 million miles), and two Perseverance demonstrates the best that we have to offer in several different categories. Nothing demonstrates this more than the “seven minutes of terror”, but let’s look at everything this rover is doing.
So, where are we going?
While one day we hope we are going to accomplish Elon Musk’s super ambitious mission of colonizing Mars, right now we are still in the learning phase of how the red plant got to its current state. Perseverance is searching for signs of ancient life on Mars but collecting rock samples in a place with high potential for finding signs of a microbial life. That location is in Jezero Crater which is a 28-mile-wide basin location in the Martian’s northern hemisphere. It is theorized that around 3.5 billion years ago, a river flowed into a body of water about the size of Lake Tahoe there.
EDL Technologies
The “seven minutes of terror” refers to the complex EDL choreography that took the spacecraft from the top of the Martian atmosphere to the rover stationary on the Martian surface. The time delay involved with relaying the data at light speed back to Earth means that the spacecraft had to accomplish this choreography all by itself. If you look at the image below, you can see the various stages and see how complicated the process is.
How in the world do you even begin to write code that can handle all of the possible conditions that could arise in landing an object on the surface of a distant planet? Seems like a bad time to have a memory leak or a windows update.
With all of this, realize that the Jezero Crater is about 28-miles-wide. That’s a relatively small area to hit, and they were able to do it flawlessly. That is amazing. One of my favorite tags of EDL is the “sky crane” (pictured above). This is where the rover is dropped onto the surface by the powered descent vehicle. The powered descent vehicle then flies as far as it can away from the site so that it doesn’t get in the rover’s way.
On The Surface
One of the interesting things about Perseverance is that it will cut intact rock cores that are about the size of a piece of chalk and leave the samples in tubes that it will store until the rover reaches the drop-off location on Mars. This way we can return the samples to Earth where we can use more precise instruments to analyze the samples.
Conclusion
I can only imagine what the engineers at NASA and JPL were feeling when they got the “Safe on Mars” being reported back. Hats off to them for such an impressive feat, and I can’t wait to see what else they can accomplish.
